﻿namespace Cn.Z
{
    public class Lunar
    {
        public bool isleap;
        public int lunarDay;
        public int lunarMonth;
        public int lunarYear;
    }

    public class Solar
    {
        public int solarDay;
        public int solarMonth;
        public int solarYear;
    }

    public class LunarSolarConverter
    {
        /* 
         * |----4位闰月|-------------13位1为30天，0为29天| 
         * */

        public static int[] lunar_month_days =
        {
            1887, 0x1694, 0x16aa, 0x4ad5, 0xab6, 0xc4b7, 0x4ae, 0xa56, 0xb52a,
            0x1d2a, 0xd54, 0x75aa, 0x156a, 0x1096d, 0x95c, 0x14ae, 0xaa4d, 0x1a4c, 0x1b2a, 0x8d55, 0xad4, 0x135a, 0x495d,
            0x95c, 0xd49b, 0x149a, 0x1a4a, 0xbaa5, 0x16a8, 0x1ad4, 0x52da, 0x12b6, 0xe937, 0x92e, 0x1496, 0xb64b, 0xd4a,
            0xda8, 0x95b5, 0x56c, 0x12ae, 0x492f, 0x92e, 0xcc96, 0x1a94, 0x1d4a, 0xada9, 0xb5a, 0x56c, 0x726e, 0x125c,
            0xf92d, 0x192a, 0x1a94, 0xdb4a, 0x16aa, 0xad4, 0x955b, 0x4ba, 0x125a, 0x592b, 0x152a, 0xf695, 0xd94, 0x16aa,
            0xaab5, 0x9b4, 0x14b6, 0x6a57, 0xa56, 0x1152a, 0x1d2a, 0xd54, 0xd5aa, 0x156a, 0x96c, 0x94ae, 0x14ae, 0xa4c,
            0x7d26, 0x1b2a, 0xeb55, 0xad4, 0x12da, 0xa95d, 0x95a, 0x149a, 0x9a4d, 0x1a4a, 0x11aa5, 0x16a8, 0x16d4,
            0xd2da, 0x12b6, 0x936, 0x9497, 0x1496, 0x1564b, 0xd4a, 0xda8, 0xd5b4, 0x156c, 0x12ae, 0xa92f, 0x92e, 0xc96,
            0x6d4a, 0x1d4a, 0x10d65, 0xb58, 0x156c, 0xb26d, 0x125c, 0x192c, 0x9a95, 0x1a94, 0x1b4a, 0x4b55, 0xad4,
            0xf55b, 0x4ba, 0x125a, 0xb92b, 0x152a, 0x1694, 0x96aa, 0x15aa, 0x12ab5, 0x974, 0x14b6, 0xca57, 0xa56, 0x1526,
            0x8e95, 0xd54, 0x15aa, 0x49b5, 0x96c, 0xd4ae, 0x149c, 0x1a4c, 0xbd26, 0x1aa6, 0xb54, 0x6d6a, 0x12da, 0x1695d,
            0x95a, 0x149a, 0xda4b, 0x1a4a, 0x1aa4, 0xbb54, 0x16b4, 0xada, 0x495b, 0x936, 0xf497, 0x1496, 0x154a, 0xb6a5,
            0xda4, 0x15b4, 0x6ab6, 0x126e, 0x1092f, 0x92e, 0xc96, 0xcd4a, 0x1d4a, 0xd64, 0x956c, 0x155c, 0x125c, 0x792e,
            0x192c, 0xfa95, 0x1a94, 0x1b4a, 0xab55, 0xad4, 0x14da, 0x8a5d, 0xa5a, 0x1152b, 0x152a, 0x1694, 0xd6aa,
            0x15aa, 0xab4, 0x94ba, 0x14b6, 0xa56, 0x7527, 0xd26, 0xee53, 0xd54, 0x15aa, 0xa9b5, 0x96c, 0x14ae, 0x8a4e,
            0x1a4c, 0x11d26, 0x1aa4, 0x1b54, 0xcd6a, 0xada, 0x95c, 0x949d, 0x149a, 0x1a2a, 0x5b25, 0x1aa4, 0xfb52,
            0x16b4, 0xaba, 0xa95b, 0x936, 0x1496, 0x9a4b, 0x154a, 0x136a5, 0xda4, 0x15ac
        };

        public static int[] solar_1_1 =
        {
            1887, 0xec04c, 0xec23f, 0xec435, 0xec649, 0xec83e, 0xeca51, 0xecc46, 0xece3a,
            0xed04d, 0xed242, 0xed436, 0xed64a, 0xed83f, 0xeda53, 0xedc48, 0xede3d, 0xee050, 0xee244, 0xee439, 0xee64d,
            0xee842, 0xeea36, 0xeec4a, 0xeee3e, 0xef052, 0xef246, 0xef43a, 0xef64e, 0xef843, 0xefa37, 0xefc4b, 0xefe41,
            0xf0054, 0xf0248, 0xf043c, 0xf0650, 0xf0845, 0xf0a38, 0xf0c4d, 0xf0e42, 0xf1037, 0xf124a, 0xf143e, 0xf1651,
            0xf1846, 0xf1a3a, 0xf1c4e, 0xf1e44, 0xf2038, 0xf224b, 0xf243f, 0xf2653, 0xf2848, 0xf2a3b, 0xf2c4f, 0xf2e45,
            0xf3039, 0xf324d, 0xf3442, 0xf3636, 0xf384a, 0xf3a3d, 0xf3c51, 0xf3e46, 0xf403b, 0xf424e, 0xf4443, 0xf4638,
            0xf484c, 0xf4a3f, 0xf4c52, 0xf4e48, 0xf503c, 0xf524f, 0xf5445, 0xf5639, 0xf584d, 0xf5a42, 0xf5c35, 0xf5e49,
            0xf603e, 0xf6251, 0xf6446, 0xf663b, 0xf684f, 0xf6a43, 0xf6c37, 0xf6e4b, 0xf703f, 0xf7252, 0xf7447, 0xf763c,
            0xf7850, 0xf7a45, 0xf7c39, 0xf7e4d, 0xf8042, 0xf8254, 0xf8449, 0xf863d, 0xf8851, 0xf8a46, 0xf8c3b, 0xf8e4f,
            0xf9044, 0xf9237, 0xf944a, 0xf963f, 0xf9853, 0xf9a47, 0xf9c3c, 0xf9e50, 0xfa045, 0xfa238, 0xfa44c, 0xfa641,
            0xfa836, 0xfaa49, 0xfac3d, 0xfae52, 0xfb047, 0xfb23a, 0xfb44e, 0xfb643, 0xfb837, 0xfba4a, 0xfbc3f, 0xfbe53,
            0xfc048, 0xfc23c, 0xfc450, 0xfc645, 0xfc839, 0xfca4c, 0xfcc41, 0xfce36, 0xfd04a, 0xfd23d, 0xfd451, 0xfd646,
            0xfd83a, 0xfda4d, 0xfdc43, 0xfde37, 0xfe04b, 0xfe23f, 0xfe453, 0xfe648, 0xfe83c, 0xfea4f, 0xfec44, 0xfee38,
            0xff04c, 0xff241, 0xff436, 0xff64a, 0xff83e, 0xffa51, 0xffc46, 0xffe3a, 0x10004e, 0x100242, 0x100437,
            0x10064b, 0x100841, 0x100a53, 0x100c48, 0x100e3c, 0x10104f, 0x101244, 0x101438, 0x10164c, 0x101842, 0x101a35,
            0x101c49, 0x101e3d, 0x102051, 0x102245, 0x10243a, 0x10264e, 0x102843, 0x102a37, 0x102c4b, 0x102e3f, 0x103053,
            0x103247, 0x10343b, 0x10364f, 0x103845, 0x103a38, 0x103c4c, 0x103e42, 0x104036, 0x104249, 0x10443d, 0x104651,
            0x104846, 0x104a3a, 0x104c4e, 0x104e43, 0x105038, 0x10524a, 0x10543e, 0x105652, 0x105847, 0x105a3b, 0x105c4f,
            0x105e45, 0x106039, 0x10624c, 0x106441, 0x106635, 0x106849, 0x106a3d, 0x106c51, 0x106e47, 0x10703c, 0x10724f,
            0x107444, 0x107638, 0x10784c, 0x107a3f, 0x107c53, 0x107e48
        };

        public static int GetBitInt(int data, int length, int shift)
        {
            return (data & (((1 << length) - 1) << shift)) >> shift;
        }

        //WARNING: Dates before Oct. 1582 are inaccurate 
        public static long SolarToInt(int y, int m, int d)
        {
            m = (m + 9)%12;
            y = y - m/10;
            return 365*y + y/4 - y/100 + y/400 + (m*306 + 5)/10 + (d - 1);
        }

        public static Solar SolarFromInt(long g)
        {
            long y = (10000*g + 14780)/3652425;
            long ddd = g - (365*y + y/4 - y/100 + y/400);
            if (ddd < 0)
            {
                y--;
                ddd = g - (365*y + y/4 - y/100 + y/400);
            }
            long mi = (100*ddd + 52)/3060;
            long mm = (mi + 2)%12 + 1;
            y = y + (mi + 2)/12;
            long dd = ddd - (mi*306 + 5)/10 + 1;
            var solar = new Solar();
            solar.solarYear = (int) y;
            solar.solarMonth = (int) mm;
            solar.solarDay = (int) dd;
            return solar;
        }

        private static bool IsLeapYear(int y)
        {
            return ((y%4 == 0 && y%100 != 0) || (y%400 == 0));
        }

        public static Solar LunarToSolar(Lunar lunar)
        {
            int days = lunar_month_days[lunar.lunarYear - lunar_month_days[0]];
            int leap = GetBitInt(days, 4, 13);
            int offset = 0;
            int loopend = leap;
            if (!lunar.isleap)
            {
                if (lunar.lunarMonth <= leap || leap == 0)
                {
                    loopend = lunar.lunarMonth - 1;
                }
                else
                {
                    loopend = lunar.lunarMonth;
                }
            }
            for (int i = 0; i < loopend; i++)
            {
                offset += GetBitInt(days, 1, 12 - i) == 1 ? 30 : 29;
            }
            offset += lunar.lunarDay;

            int solar11 = solar_1_1[lunar.lunarYear - solar_1_1[0]];

            int y = GetBitInt(solar11, 12, 9);
            int m = GetBitInt(solar11, 4, 5);
            int d = GetBitInt(solar11, 5, 0);

            return SolarFromInt(SolarToInt(y, m, d) + offset - 1);
        }

        public static Lunar SolarToLunar(Solar solar)
        {
            var lunar = new Lunar();
            int index = solar.solarYear - solar_1_1[0];
            int data = (solar.solarYear << 9) | (solar.solarMonth << 5) | (solar.solarDay);
            int solar11 = 0;
            if (solar_1_1[index] > data)
            {
                index--;
            }
            solar11 = solar_1_1[index];
            int y = GetBitInt(solar11, 12, 9);
            int m = GetBitInt(solar11, 4, 5);
            int d = GetBitInt(solar11, 5, 0);
            long offset = SolarToInt(solar.solarYear, solar.solarMonth, solar.solarDay) - SolarToInt(y, m, d);

            int days = lunar_month_days[index];
            int leap = GetBitInt(days, 4, 13);

            int lunarY = index + solar_1_1[0];
            int lunarM = 1;
            int lunarD = 1;
            offset += 1;

            for (int i = 0; i < 13; i++)
            {
                int dm = GetBitInt(days, 1, 12 - i) == 1 ? 30 : 29;
                if (offset > dm)
                {
                    lunarM++;
                    offset -= dm;
                }
                else
                {
                    break;
                }
            }
            lunarD = (int) (offset);
            lunar.lunarYear = lunarY;
            lunar.lunarMonth = lunarM;
            lunar.isleap = false;
            if (leap != 0 && lunarM > leap)
            {
                lunar.lunarMonth = lunarM - 1;
                if (lunarM == leap + 1)
                {
                    lunar.isleap = true;
                }
            }

            lunar.lunarDay = lunarD;
            return lunar;
        }
    }
}